740i 1998 blown head gasket???

Its probably a twin head monoblock type arrangement. This'll mean one gasket for the two heads.

If its single, both heads off I'm afraid.

If it comes down to £500 difference between a BMW job (& assoc. warranty) or an indy, on a £2500 job I'd go BMW. And get a written quote if you can!

How many miles on the '40 out of interest?

worrying more like!

a woman, pricing a mans job?!?

he he he!!!

Seriously though it may be 2, I don't know, but you'll be having 80% of the parts off to do one head so not much more for the pair.

I always get a written quote or at least estimate for a big job like that.

have had a cheaper quote from BMW dealer of £2k (who said they wont do work with out testing to gaurentee its headgasket at no extra charge and they will try and keep price to minimum)and one from an indy for £2400 so ill stick with BMW, car is fully loaded with Alpina wheels and full BMW service history and ive just spent £500 getting past mot and £300 on 2 new tyres, with headgaskets fixed its worth an easy £5k + (saw a non fully loaded one with slightly more mileage and no sat nav and tv go for £5200) cant sell it as it is without saying its got headgasket problem and who will buy it then???

sleeper wrote: I didn't realise how economical they were to buy! Very tempting.....

An older 7 is the best bargain on the market, especially if you're prepared to do a bit of work on them yourself.  An E32 in good condition should be cheaper to run than a fiesta if you include depreciation in your calculations because they can be had for next to nothing

Edited by Chas C

Selephant wrote: You could buy 10 E23/E28s for that!

Yeah, and they'd all be worthless rubbish. As matey
says, a 740i with head gasket probs is worth next to
nothing. Spend two grand and it then has a value of
about 5k. All part and parcel of running a modern car,
but I wouldn't swap 100 E23's for an E38. Just a
lovely car and one of the best BMW has ever made.

Whilst it's being fixed at BMW, get them to replace
the thermostat unit and the heater hose at the back
of the heads - these are a right b*stard to get to with
the heads on.

Mercedes are flagging in the build quality dept as well, the number of recent Mercedes owners that are selling their cars due to unreliability is quite staggering. 3 near me, all mid range saloons as well (not sure what they are in ther Merc range though)

If its going to set you back £2k I would definitely go to the trouble ascertaining the exact fault beforehand myself as from what your descibing none of the 'professionals' have done this 100% beyond all doubt. 

To test for a leaking head gasket a gauge can be purchased which screws into the sparkplug hole and gives a read out of the pressure ( compression ) in the cylinder. Do this for each cylinder and if its the head then one or more cylinders will give a reading below the others.

Is there any sign of overheating/Increase in water temperature ?

When a head gasket 'blows', hot exhaust gasses escape and this in turn heats up the water more than normal and hence will show up on the temperature gauge. No increase in temp reduces the chances that it is a head gasket problem.

Are there any signs of emulsion ?

When water and oil are mixed some oil is emulsified. This will show up as a specks of white gunk very similar in appearance and consistency to mayonaise on the oil filler cap.

If there are no signs of Emulsion then the water and oil are not mixing and hence this drastically reduces the chances of it being a  blown gasket, I would definitely then check the compression.

If the problem only occurred AFTER you had the radiator header tank replaced then I would serriously consider 'Buffoon at large' type causes, Caused by ignorant, incompetent and uncaring mechanics not doing their jobs properly.

Have they messed with and or replaced all the HT ( spark plug etc )  leads correctly ? have they tugged them about or oiled them up. ( Oil/gunk on the outside of the HT leads can cause misfiring )

Hope some of this helps

best of luck with it.

Edited by 735owner

Sounds very like a head gasket to me. The extra preasure can caulse many problems and leaks. Make sure they replace the radiator cap. Most people/ mechanics do not know that thse cars actually run at a computer controlled 110C (Most cars run at about 85C which is less than boiling) when the engine is under LIGHT load. This means the pressure is REQUIRED to keep the water inside the head from boiling. A loss of presure in the cooling system can caluse a headgasket to blow before the temp even increases even under light load!!!.

Great to hear you are getting your car fixed.

I really do not agree with the attutude that one should not spend money on ones car. Modern cars do not really wear out they just have failures and these things can occur ant any time during their life. almost totally independent of the mileage. As soon as you start defering maintainance and swapping your car for someone elses stuff up you start to loose the benifits of running an old car!!.

Remember the AA/Which etc running costs. Anybody who runs an old 740 should at least be able to run it for less than the new Fiesta cost of 30 pence per mile (15000). So as long as your car is one of the fastest most comfortable best looking cars on the road who cares if you have to spend 2000 on it!! once in a while.

Sounds expensive for a thermostat and a cam sensor!

Enjoy that 325...  you're paying for it anyway

im not fussed either way, anything is better then £2k!